Bright light exposure has proved to facilitate awakening. The light elevates the cortisol levels in healthy subjects. Dawn simulators are commercially available. These lighting devices increase the intensity of light prior to awakening to approximately 30 to 400 lux over a period of time ranging from 15 to 120 minutes. Then an audible alarm sounds. Dawn simulation improves the cortisol response and mood during awakening.
Document US 2003/0095476 describes an apparatus for a waking control system. The apparatus is intended to gradually introduce a stimulus, such as light, before a planned wake-up time, in order to wake the individual gradually so as to promote wellness. The document further describes the seasonal amount of light that is taken into account, as determined by the date. Document GB2422447 describes a dawn simulator alarm clock.
Document JP6314595 describes a lighting system. The lighting system turns on a lighting lamp and its illuminance is controlled to 2000 lux or more, while the related color temperature is controlled to 6000 Kelvin or more.
Lighting devices have the common characteristic feature that they use one lamp and that the transmitted light is white light.
Lighting devices comprising one or more light sources capable of generating different types of light of different colors are known in the art.
For instance, BE 1015507 describes a lighting assembly with two or more white lights, at least one of which is dimmable, and a separate color filter is provided on one side for each light, while there are no or no different color filters on the other side.
U.S. Pat. No. 6,688,753 describes a lighting device comprising a first lighting element, preferably a compact fluorescent discharge vessel and a second lighting element, preferably comprising a plurality of LEDs. During operation, the first lighting element has a comparatively high light output. In operation, the second lighting element has a light output which is relatively low in comparison with that of the first lighting element. The first or the second lighting element, or both, can be switched on. The lighting device allows remote-controlled switching between orientation light (night lamp) and normal light, using a toggle function in the lighting device.